Journal
JOURNAL OF CELLULAR BIOCHEMISTRY
Volume 95, Issue 5, Pages 1042-1056Publisher
WILEY
DOI: 10.1002/jcb.20486
Keywords
smooth muscle; protein partners; K-protein; ERK1/2; 2D gel electrophoresis; cycloheximide; isoforms
Categories
Ask authors/readers for more resources
Coronary artery blockage, due to cardiovascular disease, is routinely treated by either balloon-angioplasty or bypass surgery. The limited success of these clinical interventions is due at least in part to smooth muscle cell (SMC) proliferation. Here we show that heterogeneous nuclear ribonucleoprotein complex K (hnRNP-K) protein levels increase in SMC with response to serum stimulation in vitro, in the aortas from an animal model of atherosclerosis, and in occluded human vein segments. hnRNP-K is a multi-functional protein that has been studied primarily in cancer cells and has been suggested to play a role in cell cycle progression. We show that in untransformed, cultured SMC, hnRNP-K protein sub-cellular localization modulates through the cell cycle in both the cytoplasm and nucleus. Using cycloheximide, we observed that cytoplasmic accumulation of hnRNP-K protein at later time points in the cell cycle occurred with a concomitant decrease in nuclear hnRNP-K protein, suggesting a translocation of nuclear hnRNP-K protein to the cytoplasm. Also, because we did not observe an increase in hnRNP-K protein at early time points in the cell cycle in the presence of cycloheximide, we propose that the early increase in cytoplasmic hnRNP-K protein following serum stimulation is due to new hnRNP-K protein synthesis. When present in the cytoplasm, hnRNP-K is part of a multi-protein complex that consists of at least two other proteins, calponin and ERK1/2. Our findings from this study are intriguing because they suggest that cytoplasmic hnRNP-K in SMC is part of a signaling complex that may be involved in growth-stimulated post-transcriptional regulation. J. Cell. Biochem. (c) 2005 Wiley-Liss, Inc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available